Derivative Financial Instruments and Off-balance sheet Financial Instruments (Details 5) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013 counterparties	Dec. 31, 2012 counterparties
Derivative Financial Instruments and Off-balance sheet Financial Instruments
Cash and securities pledged as collateral by counterparties	$ 17
Securities pledged as collateral to counterparties	23
Collateral posted under MNAs, credit-risk-contingent provisions in a liability position	14	25
Collateral posted under MNAs for contracts without credit-risk-contingent liabilities	9
Credit Derivatives
Number of counter-parties	9	10
Notional amount	1,783	6,893
Credit exposure	15	33
Exposure, net of collateral	3	5
Gross liability fair value of contracts containing credit-risk-contingent features	28	65
Gross asset fair value of contracts containing credit-risk-contingent features and subject to MNAs	(11)	(31)
Collateral posted under MNAs for contracts containing credit-risk-contingent features	(14)	(25)
Maximum amount of additional exposure for contracts with credit-risk-contingent features if all features were triggered concurrently	3	9
A+
Credit Derivatives
Number of counter-parties	1	2
Notional amount	22	29
Credit exposure	1	1
Exposure, net of collateral	1	1
A
Credit Derivatives
Number of counter-parties	5	4
Notional amount	1,628	2,450
Credit exposure	9	13
Exposure, net of collateral	2	2
A-
Credit Derivatives
Number of counter-parties	1	3
Notional amount	24	797
Credit exposure	1	8
Exposure, net of collateral		2
BBB+
Credit Derivatives
Number of counter-parties	1	1
Notional amount	33	3,617
Credit exposure	3	11
BBB
Credit Derivatives
Number of counter-parties	1
Notional amount	76
Credit exposure	$ 1